Then, he began playing for Bill Belichick. Moss' mindset regarding his own football knowledge changed in a hurry. Only then did he learn the intricacies of his sport from "A to Z," as the 49ers wide receiver now puts it.

"Everybody knows that Bill Belichick is a so-called genius," Moss said. "He changes it up every week, so there's not really much input that I can give for the week."

Moss returns to Foxborough, Mass., this weekend with his new team to face the high-scoring Patriots (10-3) in prime time — a matchup of Tom Brady and the AFC's top offense against NFL sacks leader Aldon Smith and the NFC's No. 2 defense.

"I've said time and time again, before I got to New England, I thought I knew a lot about football," Moss said. "But I think he taught me a lot from A to Z. I still carry it to this day. The compliments are good and I respect coach Belichick and that organization still to this day. Hopefully, we'll have a good game coming up Sunday night. I look forward to the game, and hope the fans do, too."

The 35-year-old Moss hardly has the playmaking role as a 14th-year pro that he did as a youngster in the league, yet that didn't stop Belichick from piling on the praise this week.

Moss has 21 catches for 326 yards and two touchdowns this season for the San Francisco 49ers (9-3-1). Not bad for a guy who spent the 2011 season out of football following a frustrating year in which he bounced from the Patriots to the Vikings to the Titans.

"He's the greatest deep-ball receiver I think that's ever played," Belichick said. "Nobody runs better patterns, better at the deep part of the field, than Randy Moss can. I still see him doing that. You have to respect his ability to stretch the field so deep and get behind you. It's hard to take that away and defend everything else that he can do. He's an explosive, dynamic player. Probably the smartest receiver I've ever coached. I know he absolutely knows what he's doing, knows what the defense is doing."

Moss said earlier this week he didn't watch New England's Monday night rout of the Houston Texans because he already knew what the Patriots bring with Brady under center. Many remember that Moss' best season came for the Patriots in 2007, when he caught 98 passes for 1,493 yards and a single-season record 23 touchdowns in helping lead New England to a 16-0 regular season.

When asked if he sees any similarities in how the Patriots and his current 49ers franchise are run, Moss was guarded.

"I don't really want to get into all that because whatever I say is going to be the wrong thing to say," he said. "So, basically, I'll leave it at, I've still got love and respect for the New England Patriots and everything that we did as a team up there. But now I'm a 49er so, like I said, hopefully we go up there Sunday night and we give it a good game."

Moss signed a one-year deal with the 49ers in mid-March only hours after he worked out with former NFL quarterback and coach Jim Harbaugh. Moss has been appreciative of a fresh start, and mentored younger players such as wideout Michael Crabtree.

While Moss' respect for Brady goes unsaid, the veteran receiver also appreciates how second-year pro Colin Kaepernick has handled himself after being promoted to starter four games ago in place of Alex Smith.

"Most second-year quarterbacks are just waiting in the shadow and just waiting to get their shot. I think Kap's been able to come in and just lead us as a whole unit," Moss said. "Any time a guy can come in and lead like that, and I don't mean verbally, but leading by example, is what we as football players look for in a player. Especially in a quarterback. So I really just compliment his leadership and going out there and leading our offense up and down the field."

The Niners realize Sunday's game will probably be won or lost by their defense, and that they need to score, too.

"I think you've got to do a little bit of everything," defensive coordinator Vic Fangio said Thursday. "Obviously when you're playing a team that scores the way this team does, you're going to have to score some points, too."

Aldon Smith, whose 19 ½ sacks leave him three from Michael Strahan's single-season record set in 2001 with the New York Giants, has one thought for anybody questioning whether San Francisco's defense can keep up Sunday.

"We can stop 'em, yeah, yeah!" Smith said. "We've played good offenses before. It's not the first offense we've played that has talent."

Notes: WR Mario Manningham, who missed last Sunday's win against the Dolphins, is still nursing an injured right shoulder. He caught balls during Thursday afternoon's practice. "I'm getting there," Manningham said, patches from an electric stimulation machine attached to the shoulder as he walked through the locker room. "Taking it day by day. We'll see." ... Aldon Smith announced Thursday he will donate $5,099 for each of his regular-season sacks to Boys & Girls Clubs of San Francisco and The Peninsula. He said he has never spoken to nor met Strahan.